Success of micropropagated woody landscape plants under northern growing conditions and changing environment
1University of Oulu, Faculty of Science, Department of Biology
|Online Access:||PDF Full Text (PDF, 2.6 MB)|
|Persistent link:|| http://urn.fi/urn:isbn:9789514260780
|Publish Date:|| 2009-12-01
|Thesis type:||Doctoral Dissertation
|Defence Note:||Academic dissertation to be presented with the assent of the Faculty of Science of the University of Oulu for public defence in Kuusamonsali (Auditorium YB210), Linnanmaa, on 11 December 2009, at 12 noon
Doctor Michael Kiehn
Docent Leena Lindén
Plant registration and selection work aimed at identifying the best genotypes for northern landscaping has been carried out in Finland since the 1980’s. In the University of Oulu Botanical Gardens, micropropagation methods have been developed for several woody plant taxa registered during the POHKAS (Northern Hardy Plants) project. Micropropagation is an effective method to conserve valuable genetic characteristics and to produce plantlets from woody species with limited mother stock material and in a limited time period.
In this study the long-term field phenology and success of 19 micropropagated shrub and tree taxa was followed in plant selection experiments. Experiments were conducted at four northern field sites presenting different climatic conditions. Of the phenological monitoring parameters, the onset of foliation and flowering in the field revealed a strong relation to spring time temperature, being obviously latest to occur in northernmost site. The gradient between southern and northern sites for autumn phenology was not so obvious. However, between the different genotypes, the greatest differences were observed in the timing of autumn colouration and defoliation. Winter hardiness also showed clear differences between genotypes. Of the success parameters, it was most decisive as winter hardy genotypes had a higher occurrence of flowers and ornamental appearance, for example in Rosa majalis ‘Tornedal’. Some of these hardy genotypes with known characteristics were introduced to northern tourism areas to create examples of sustainable landscaping. Further, a list of potential plants for different northern sites was compiled.
Special forms with both scientific and ornamental value are occasionally found in wild species. One example of this is the red-leaved form of a pubescent birch, Betula pubescens f. rubra, which was studied in the plant selection experiments, and was used as a model tree to evaluate the role of anthocyanins in northern plants in a case study of northern birches. In the case study, the red-leaved pubescent birch showed some differences in flavonoid responses and growth rate in comparison to Betula pubescens and Betula pubescens ssp. czerepanovii. Phenology of the B. p. f. rubra was corresponding to that of the B. pubescens.
For cultivated woody plants the most important selection criteria for the northern areas are the suitability to local climate i.e. timing of phenological events and winter hardiness. Foliar anthocyanins seem to increase adaptation to northern growing conditions with high light intensity and low temperature.
Acta Universitatis Ouluensis. A, Scientiae rerum naturalium
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